Hey, I\'m working on a web app that has a login dialog that works like this:
The truth is, you can't force the browser to ask. I'm sure the browser has it's own algorithm for guessing if you've entered a username/password, such as looking for an input of type="password" but you cannot set anything to force the browser.
You could, as others suggest, add user information in a cookie. If you do this, you better encrypt it at the least and do not store their password. Perhaps store their username at most.